Geochemistry of lead contaminated wetland soils amended with phosphorus

Strawn, Daniel G.; Hickey, Patrick J.; Knudsen, Andrew; Baker, Leslie L.

doi:10.1007/s00254-006-0464-1

Cited by 17 publications

(29 citation statements)

References 34 publications

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“…However, the results of some other works made the formation of the precipitation questionable. No pyromorphite precipitation was detected in certain research (Cotter-Howells et al 1994;Strawn et al 2007). In some reports, Pb was found predominantly combined with iron and manganese oxides (Strawn et al 2007).…”

Section: Different Roles Of P Amendment On Soil and Plant Pb Availabimentioning

confidence: 81%

“…No pyromorphite precipitation was detected in certain research (Cotter-Howells et al 1994;Strawn et al 2007). In some reports, Pb was found predominantly combined with iron and manganese oxides (Strawn et al 2007). Furthermore, the feasibility of investigating the species of Pb with sequential extraction and the formation of pyromorphite with XRD was also questioned (Chrysochoou, Dermatas, and Grubb 2007;Scheckel et al 2005).…”

Section: Different Roles Of P Amendment On Soil and Plant Pb Availabimentioning

confidence: 81%

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Phosphorus Amendment of a Lead-Spiked Soil with Low Phosphorus Availability: Roles of Phosphorus on Soil and Plant Lead

Xing

et al. 2012

Communications in Soil Science and Plant Analysis

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Phosphorus (P) is both a macronutrient for plants and an effective amendment to reduce lead (Pb) toxicity in soil.Thus, in Pb-polluted soil with low P availability, P will act as a nutrient as well as a Pb-immobilizing agent. However, this has not been fully investigated. A soil with 2.50 mg kg −1 Olsen P was spiked with soluble Pb and then amended with superphosphate to examine the effect of P on soil Pb availability and ryegrass (Lolium perenne L. cv. Aubisque) growth. It was found that P/Pb = 2 increased ryegrass yield by 804% and decreased root Pb concentration and soil diethylenetriaminepentaacetic acid (DTPA)-extractable Pb concentration by 25.6% and 1.0%, respectively. As P amendment increased to P/Pb = 4, both plant yield and root Pb concentration declined compared with P/Pb = 2. Results of the sequential extraction indicated that the proportion of carbonate phase Pb decreased, while that of the manganese oxide phase increased as P was added. The proportion of residual Pb was little affected by the amendment. The results suggest that in soils with low P availability and high Pb availability, availability of soil Pb and root concentration of Pb are less affected, whereas the toxicity of Pb is greatly depressed by the P amendment; P/Pb = 2 is high enough to alleviate the stresses of low P availability.

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Section: Different Roles Of P Amendment On Soil and Plant Pb Availabimentioning

confidence: 81%

Section: Different Roles Of P Amendment On Soil and Plant Pb Availabimentioning

confidence: 81%

Phosphorus Amendment of a Lead-Spiked Soil with Low Phosphorus Availability: Roles of Phosphorus on Soil and Plant Lead

Xing

et al. 2012

Communications in Soil Science and Plant Analysis

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“…Yang and Mosby (2006) tested different methods of application of H 3 PO 4 in Pb contaminated soils and reported that rototilling was the most effective in terms of the soluble P homogeneity and the reduction of Pb bioaccessibility in the treated soil zone. Strawn et al (2007) also studied H 3 PO 4 amendments on Pb contaminated soils by means of XRD and EMPA techniques and concluded that that after addition of P, distinct mineralogical changes occurred in soils, such as oxidation of siderite. In the original soil Pb was associated with poorly crystalline Fe and Mn oxides and the P added resulted primarily associated with Fe oxide phases.…”

Section: Amendments With Water-soluble Phosphatesmentioning

confidence: 98%

Phosphates for Pb immobilization in soils: a review

2008

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In its soluble ionic forms, lead (Pb) is a toxic element occurring in waters and soils mainly as the result of human activities. The bioavailability of lead ions can be decreased by complexation with various materials in order to decrease their toxicity. Pb chemical immobilization using phosphate addition is a widely accepted technique to immobilize Pb from aqueous solution and contaminated soils. The application of different P amendments cause Pb in soils to shift from forms with high availability to the most strongly bound Pb fractions. The increase of Pb in the residual or insoluble fraction results from formation of pyromorphite Pb 5 (PO 4 ) 3 X where X = F, Cl, Br, OH, the most stable environmental Pb compounds under a wide range of pH and Eh natural conditions. Accidental pyromorphite ingestion does not yield bioavailable lead, because pyromorphite is insoluble in the intestinal tract. Numerous natural and synthetic phosphates materials have been used to immobilize Pb: apatite and hydroxyapatite, biological apatite, rock phosphate, soluble phosphate fertilizers such as monoammonium phosphate, diammonium phosphate, phosphoric acid, biosolids rich in P, phosphatic clay and mixtures. The identification of pyromorphite in phosphate amended soils has been carried out by different non destructive techniques such as X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, X-ray absorption fine structure, transmission electron microscopy and electron microprobe analysis. The effectiveness of in situ Pb immobilization has also been evaluated by selective sequential extraction, by the toxicity leaching procedure and by a physiologically based extraction procedure simulating metal ingestion and gastrointestinal bioavailability to humans. Efficient Pb immobilization using P amendments requires increasing the solubility of the phosphate phase and of the Pb species phase by inducing acid conditions. Although phosphorus addition seems to be highly effective, excess P in soil and its potential effect on eutrophication of surface water, and the possibility of As enhanced leaching remains a concern. The use of mixed treatments may be a useful strategy to improve their effectiveness in reducing lead phyto-and bioavailability.

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“…[1,2,3] Sequential extraction of soils have shown that Pb is often associated with Fe and Mn oxide minerals and organic / sulphide fractions. [4,5,6] For example, Strawn et al, [7] showed that Pb was associated with Mn oxides and poorly crystallised Fe oxides, using electron microprobe and X-ray diffraction analyses of contaminated wetland soils. However, Lang & Kaupenjohann [8] suggested that Pb phosphates, especially pyromorphites, are the most stable Pb-containing minerals under a wide range of conditions, and so would be expected to be present in Pb-contaminated soils.…”

Section: Introductionmentioning

confidence: 99%

Fractionation of lead in soil by isotopic dilution and sequential extraction

et al. 2011

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The chemical reactivity of lead in soil is difficult to assess and depends on both soil conditions and the origins of the lead. This paper tests the combined application of lead isotopic techniques and chemical extraction to our understanding of lead fractionation in soils. Possibly against expectation, it appears that the 'reactivity' of lead can be high and yet there is tentative evidence that the original source of the metal affects its fractionation in soil, even after long contact times. Abstract 'Reactivity' or 'lability' of lead is difficult to measure using traditional methods. We investigated the use of isotopic dilution with 204 Pb to determine metal reactivity in four soils historically contaminated with contrasting sources of Pb, including (i) petrol-derived Pb, (ii) Pb/Zn mine-spoil, (iii) long-term sewage sludge application and (iv) C19 th urban waste disposal; total soil Pb concentrations ranged from 217 -13600 mg kg -1 . A post-spike equilibration period of three days and 5.0 x 10 -4 M EDTA electrolyte provided reasonably robust conditions for measuring isotopically-exchangeable Pb although in acidic organic soils a dilute Ca(NO 3 ) 2 electrolyte may be better to avoid mobilisation of 'non-labile' Pb. Results showed that the reactive pool of soil Pb is often larger than may be intuitively expected but varies with the original Pb source. A comparison of isotopic exchangeability with the results of a sequential extraction procedure showed that (isotopically) 'non-labile' Pb may be broadly equated with 'residual' Pb in organic soils. However, in mineral soils the 'calcareous' and 'oxide-bound' Pb fractions included non-labile forms of Pb. De-coupling the isotopic signature of labile and nonlabile Pb pools suggested that, despite prolonged contact with soil, differences between the lability of the original contaminant and the native soil Pb may remain.

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Geochemistry of lead contaminated wetland soils amended with phosphorus

Cited by 17 publications

References 34 publications

Phosphorus Amendment of a Lead-Spiked Soil with Low Phosphorus Availability: Roles of Phosphorus on Soil and Plant Lead

Phosphorus Amendment of a Lead-Spiked Soil with Low Phosphorus Availability: Roles of Phosphorus on Soil and Plant Lead

Phosphates for Pb immobilization in soils: a review

Fractionation of lead in soil by isotopic dilution and sequential extraction

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